/*
 * Copyright 2002-2013 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.security.web.csrf;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * An API to allow changing the method in which the expected {@link CsrfToken}
 * is associated to the {@link HttpServletRequest}. For example, it may be
 * stored in {@link HttpSession}.
 *
 * @see HttpSessionCsrfTokenRepository
 *
 * @author Rob Winch
 * @since 3.2
 *
 */
public interface CsrfTokenRepository {

    /**
     * Generates a {@link CsrfToken}
     *
     * @param request
     *            the {@link HttpServletRequest} to use
     * @return the {@link CsrfToken} that was generated. Cannot be
     *         null.
     */
    CsrfToken generateToken(HttpServletRequest request);

    /**
     * Saves the {@link CsrfToken} using the {@link HttpServletRequest} and
     * {@link HttpServletResponse}. If the {@link CsrfToken} is null, it is the
     * same as deleting it.
     *
     * @param token
     *            the {@link CsrfToken} to save or null to delete
     * @param request
     *            the {@link HttpServletRequest} to use
     * @param response
     *            the {@link HttpServletResponse} to use
     */
    void saveToken(CsrfToken token, HttpServletRequest request,
            HttpServletResponse response);

    /**
     * Loads the expected {@link CsrfToken} from the {@link HttpServletRequest}
     *
     * @param request
     *            the {@link HttpServletRequest} to use
     * @return the {@link CsrfToken} or null if none exists
     */
    CsrfToken loadToken(HttpServletRequest request);
}
